Why Being Underweight May Increase Suicide Risk More Than Obesity

A new large-scale study from South Korea suggests that people who are underweight face a significantly higher risk of dying by suicide than those who are overweight or even obese. This surprising connection between suicide risk and body weight is causing researchers and mental health professionals to rethink how we view physical and emotional health.

What Did the Study Find?

Researchers analyzed data from over 4 million adults in South Korea using the country’s National Health Information Database. They tracked health records from 2009 to 2021 to find patterns between body mass index (BMI) and suicide deaths.

Here’s what they discovered:

• Underweight individuals had a 44% higher chance of dying by suicide than those with normal weight.

• Overweight and obese individuals had a lower suicide risk, by 21% and 29% respectively.

The study factored in mental health conditions like depression and schizophrenia, as well as lifestyle factors such as alcohol use and income. Even after adjusting for these variables, body weight remained strongly linked to suicide risk.

Why Might Being Underweight Raise Suicide Risk?

Researchers believe the connection could be due to biological and psychological factors. Being underweight is often associated with poor nutrition, hormonal imbalances, and reduced serotonin levels—all of which can affect mood and mental stability.

Social pressures, isolation, and eating disorders may also play a role. Individuals who are underweight may face stigma or internal struggles with body image that worsen existing mental health conditions.

Rethinking the Role of Body Weight in Suicide Prevention

This study suggests that suicide risk and body weight may be more connected than we thought. Traditionally, suicide prevention efforts have focused on mental health symptoms like depression and anxiety. However, this research highlights the need to also consider physical health and nutritional status—especially in people who are chronically underweight.

Suicide Risk and Body Weight in the Bigger Picture

Although this study was conducted in South Korea, its findings may have implications around the world. Suicide is a leading cause of death globally, and understanding all the factors involved can help professionals develop better prevention strategies.

In particular, this research opens doors for exploring emerging therapies that consider both brain and body. Tools like neurofeedback, biofeedback, and even light therapy may support treatment plans that address the physiological roots of mental distress.

Conclusion

This groundbreaking study is a reminder that mental health is not just about the mind—it’s also about the body. Being underweight isn’t just a physical health issue; it may also signal an increased risk of emotional crisis. Future therapies and prevention strategies should take this body-brain connection into account to better support those at risk.

Read more at interventionalpsychiatry.org

References

1. Lee, J., Lee, S.-H., Kim, M.-K., et al. (2025). Inverse association between obesity and suicidal death risk. BMC Psychiatry. https://doi.org/10.1186/s12888-025-04756-1

World Health Organization. (2023). Suicide worldwide in 2023: Global health estimates. https://www.who.int/publications/i/item/9789240067294